Definition of a Security Value Determined by Limulus Amebocyte Lysate Assay Targeting the Recombinant Human Epidermal Growth Factor

The limulus amebocyte lysate (LAL) assay is the most widely used test, required by FDA, in quality control for all parenteral drugs in their last-stage manufacturing process previous to the final formulation. However, the rabbit pyrogen test (RPT) is still required in some United States Pharmacopeia (USP) monographs to allow human and animal vaccine batch release. Hence, the correlation between both endotoxin detection tests targeting recombinant human epidermal growth factor (rhEGF) as active molecule was assessed. From the end point chromogenic LAL test initial validation, a correlation coefficient of at least 0.980 in the endotoxin concentration range from 0.5 to 0.06 endotoxin units (EU)/mL was obtained. In the RPT, the specificity of the animal febrile response was previously evaluated. The authors also demonstrated that the LAL enzymatic cascade activation and the induction of the febrile mechanism in rabbits are due to specific bacterial endotoxin contaminants and not linked with rhEGF protein. Finally, a value of 5 EU per 20 pg rhEGF, measured by end point chromogenic LAL, was defined as the security value to be used as the RPT limit.